diff options
Diffstat (limited to 'include/crypto/curve25519.h')
-rw-r--r-- | include/crypto/curve25519.h | 73 |
1 files changed, 73 insertions, 0 deletions
diff --git a/include/crypto/curve25519.h b/include/crypto/curve25519.h new file mode 100644 index 0000000000..ece6a9b5fa --- /dev/null +++ b/include/crypto/curve25519.h @@ -0,0 +1,73 @@ +/* SPDX-License-Identifier: GPL-2.0 OR MIT */ +/* + * Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. + */ + +#ifndef CURVE25519_H +#define CURVE25519_H + +#include <crypto/algapi.h> // For crypto_memneq. +#include <linux/types.h> +#include <linux/random.h> + +enum curve25519_lengths { + CURVE25519_KEY_SIZE = 32 +}; + +extern const u8 curve25519_null_point[]; +extern const u8 curve25519_base_point[]; + +void curve25519_generic(u8 out[CURVE25519_KEY_SIZE], + const u8 scalar[CURVE25519_KEY_SIZE], + const u8 point[CURVE25519_KEY_SIZE]); + +void curve25519_arch(u8 out[CURVE25519_KEY_SIZE], + const u8 scalar[CURVE25519_KEY_SIZE], + const u8 point[CURVE25519_KEY_SIZE]); + +void curve25519_base_arch(u8 pub[CURVE25519_KEY_SIZE], + const u8 secret[CURVE25519_KEY_SIZE]); + +bool curve25519_selftest(void); + +static inline +bool __must_check curve25519(u8 mypublic[CURVE25519_KEY_SIZE], + const u8 secret[CURVE25519_KEY_SIZE], + const u8 basepoint[CURVE25519_KEY_SIZE]) +{ + if (IS_ENABLED(CONFIG_CRYPTO_ARCH_HAVE_LIB_CURVE25519)) + curve25519_arch(mypublic, secret, basepoint); + else + curve25519_generic(mypublic, secret, basepoint); + return crypto_memneq(mypublic, curve25519_null_point, + CURVE25519_KEY_SIZE); +} + +static inline bool +__must_check curve25519_generate_public(u8 pub[CURVE25519_KEY_SIZE], + const u8 secret[CURVE25519_KEY_SIZE]) +{ + if (unlikely(!crypto_memneq(secret, curve25519_null_point, + CURVE25519_KEY_SIZE))) + return false; + + if (IS_ENABLED(CONFIG_CRYPTO_ARCH_HAVE_LIB_CURVE25519)) + curve25519_base_arch(pub, secret); + else + curve25519_generic(pub, secret, curve25519_base_point); + return crypto_memneq(pub, curve25519_null_point, CURVE25519_KEY_SIZE); +} + +static inline void curve25519_clamp_secret(u8 secret[CURVE25519_KEY_SIZE]) +{ + secret[0] &= 248; + secret[31] = (secret[31] & 127) | 64; +} + +static inline void curve25519_generate_secret(u8 secret[CURVE25519_KEY_SIZE]) +{ + get_random_bytes_wait(secret, CURVE25519_KEY_SIZE); + curve25519_clamp_secret(secret); +} + +#endif /* CURVE25519_H */ |